Influence of perceived difficulty of cases on physicians' diagnostic reasoning.

PURPOSE: While diagnosing problems, physicians frequently switch from nonanalytical to reflective reasoning. The conditions inducing doctors to reflect are largely unknown. The authors investigated whether a shift to reflection occurs when physicians perceive a case as problematic, and its effects on diagnostic accuracy. METHOD: The authors conducted two within-subjects experiments in Brazilian teaching hospitals in 2007. In Experiment 1, 20 medical residents diagnosed the same 10 clinical cases under two experimental conditions: a nonproblematic versus a problematic context. (The latter was created by informing participants that other physicians failed to diagnose the case previously.) In addition, participants judged whether a set of medical concepts were related to the case, and response time was measured. In Experiment 2, 18 residents diagnosed two cases while thinking aloud. The authors hypothesized that a case perceived as problematic would trigger reflection, leading to higher diagnostic accuracy, lower response times for recognizing concepts (Experiment 1), more time for diagnosing, and more elaborate think-aloud protocols (Experiment 2). RESULTS: Experiment 1: Accuracy of diagnosis was significantly higher within the problematic context, and participants were faster in deciding whether concepts were related to the case. The same cases were evaluated as more complex and less frequently seen. Experiment 2: Time spent on diagnosis, memory for case findings, and inferences derived from the cases were significantly higher within the problematic context. CONCLUSIONS: A context perceived as problematic induced reflection in the participating clinicians, as indicated by lower response times, more time spent on diagnosis, and more elaborate protocols. Reflective reasoning comprised more careful analysis of findings and alternative diagnoses, and increased diagnostic accuracy.